Extruders are useful tools for forming a variety of artwork and sculptures, including clay-based artwork and products. When operated correctly, an extruder should form an extruded product (i.e., an extrusion) with a substantially constant cross-section. However, due to variations in shape between separate pieces in a clay extruder, gaps can form that interrupt the consistency of the cross-section of an extrusion. Small gaps may exist between the barrel and the piston when the shape of the piston does not match exactly with the inner surface of the barrel extruder, thereby allowing clay to “leak-back” behind the piston during extrusion. Small gaps may also exist between the end of the barrel and an attached die. Clay may also exit through these gaps as the clay is being extruded, creating an inconsistent extrusion. Typically, when uniform clay is utilized, some degree of inconsistency can be tolerated; however, in more sophisticated arts, a uniform extrusion is essential as the material placed into the extruder is strategically constructed from many different types/colors of clay, and therefore conventional extruders are unacceptable for use in such techniques. Therefore, it is desirable to have a device that seals the various gaps that are present in the barrel of an extruder to produce as consistent a cross-section of material as possible for an extrusion. Accordingly, there remains a need for further contributions in this area of technology.